Wind tunnel studies provide solutions to a wide range of aerodynamic problems, including the effect of drag, aircraft lifting characteristics, static stability, pressure distributions, and flutter characteristics. Data are usually acquired through the measurement of forces and moments acting upon a model and by changes produced in the airstream by the model. The fundamental instrumentation approach for detecting and measuring these effects is based upon providing a supporting structure for the model in which reactive forces and moments are generated in maintaining the model virtually motionless with respect to the wind tunnel structure. The reactions to yaw, pitch, roll, lift, side and drag components can then be effectively isolated from each other and separately detected.
To guarantee the accuracy of the measurements, it is essential to reduce any collateral effects resulting from interference caused by the supporting structure. For example, if the support attached to the model interferes with the normal flow of air around the model, this interference will create an error in the measurement of data. Similarly, if the supporting structure causes a distortion of the configuration geometry of the model, the accuracy of the determination of reacting moments and forces will be reduced.